Phenol extraction of hydrocarbons with alcohol solvent modifier



PHENOL EXTRACTIO OF' HYDROCARBONS WITH ALCOHOL SOLVENT MODIFIER Filed Aug. 29, 1955 Sept. 1, 1959 A J SHMIDL .2,902,444`

A T TOR/VE United States Patent Office 2,902,444 Patented Sept.. 1, 1959 PHENOL EXTRACTION OF HYDROCARBONS WITH ALCOHOL SOLVENT MODIFIER` Albert J. Shmidl, Baytown, Tex., assignor, by mesne assignments, to Esso Research and Engineering Company, Elizabeth, NJ., a corporation of Delaware Application August 29, 1955, Serial No. I530,953

'3 Claims. (Cl. 208-323) The present invention is directed to a method for solvent extracting hydrocarbon mixtures. More particularly, the invention is directed to extraction of hydrocarbon mixtures with a phenol solvent. specific aspects, the invention is concerned with modifying a phenol solvent for separating hydrocarbons.

The present invention may be briefly described as involving a method for separating predominantly saturated from predominantly aromatic hydrocarbons in which a mixture of said hydrocarbons is contacted under extraction conditions with a solvent mixture of phenol and a small but effective amount of a substantially water-insoluble aliphatic alcohol to form an extract phase and a rafiinate phase. The two phases are separated from each other and the solvent mixture is separately recovered from each of said phases.

The water-insoluble aliphatic alcohol is suitably a saturated aliphatic alcohol, such as, for example, hexyl, heptyl, octyl, nonyl and decyl alcohols which boil in the range from about 275 to about 450 F. Isomers of these alcohols such as 2-ethyl hexanol, 2-methylpentanol5, 2,3-dimethyl heptanol-6, may also be used.

The alcohols may suitably be used in a small but effective amount in the range from about 3% to about 10% by volume of the solvent mixture. A preferred amount is about 5% by volume with octyl alcohols which are also preferred.

The extraction conditions employed in the practice of the present invention may suitably include a temperature in the range from about 100 F. to about 250 F. with good results being obtained at about 110 F. with octyl alcohols.

The amount of alcohols used based on the hydrocarbon may range from about an equal amount up to about 300 volume percent. These amounts of phenol may be added incrementally and in stages as may be desired.

The hydrocarbon feed to the present invention may suitably be hydrocarbon fractions boiling in the range from about 500 up to about l000 F. and may suitably include fractions in the kerosene, gas oil, heating oil, and lubricating oil fractions in this boiling range. Other lower boiling fractions may be used but when a hydrocarbon fraction boiling below the boiling point of phenol is employed, the extract and ratinate phases will be distilled from the solvent mixture rather than the solvent mixture being distilled from the hydrocarbons.

The present invention will be further illustrated by reference to the drawing in which the single ligure is in the form of a flow diagram.

Referring now to the drawing, numeral 11 designates a solvent extraction zone comprised of a plurality of extraction stages and represented by an extraction tower provided with suitable internal liquid-liquid contacting means, such as bafe plates, distributing means, bell caps, and the like. It will also be understood that extraction zone 11 includes means for inducing rellux and means for adjusting temperatures in order to obtain the best results.

In its more` Introduced into zone 11 by Way of line 12 is a hydrocarbon feed which suitably may be a lubricating oil fraction. Also introduced into tower 11 by way of line 13 isa solvent mixture of phenol and an aliphatic alco` hol, such as octyl alcohol, which is arranged to flow countercurrently to the oil feed introduced by line 12.

Removed from zone 11 `by way of line 14 is a raiinate phase Iwhich is introduced thereby into a stripping zone 15.` Withdrawn from tower 11 by line- 16 is an extract phase which is introduced thereby into a second stripping zone 17. A

Stripping zone 15 is provided with a heating means illustrated by steam coil 18 for adjustments of tempera* ture and pressure for removal of solvent mixture by way of line 19 and for recovery of raffinate by way of line 20.

In stripping zone 17, the solvent mixture is removed from the extract phase by adjustment of temperatures and pressures by heating means illustrated by steam coil 21. The solvent mixture is removed from zone 17 by line 22 and the stripped extract phase is recovered by line 23.

The solvent mixtures from zones 15 and 17 are admixed inline 22 and re-introduced into line 13 for re-use in zone 11.

The ratlinate phase withdrawn from zone 15 after stripping of the solvent mixture therefrom is suitable for use as a lubricating oil. v

In order to illustrate the invention further, the following examples are presented to show the advantages of using the improved solvent:

A base lubricating oil fraction from a Coastal crude was extracted with two percent treats of phenol. The same quantity of phenol containing 5 percent water was compared as an `extractive agent with phenol containing 5 percent octyl alcohol. These runs` were made in batch equipment and the solvent was mixed with the base lubricating oil fraction for 30 minutes and settled for 45 minutes. The extract phase was separated from the raffinate phase and the rainates from the several operations were stripped with steam to remove solvent therefrom and then the stripped raiinates were dried by blow ing with an inert gas. Inspection of the ranates with yields and other pertinent data are presented in the following table:

TABLE Extraction of Coastal lub dlstzllates Experiment No 1 2 3 4 Phenol, Vol. Percent of Charge 1 200 1 200 l 200 2 150 Water, Percent on Phenol 5 Octyl Alcohol, Percent 5 5 5 Mlscibility Temperature, l3` 200 166 166 Treating Temperature, F 170 130 110 110 Ranate Yield Percent; of Charge 70. 5 54. 2 6l. 5 68. 2 Gravity, APF' 25.0 25.8 25.5 24. 9 Viscosity at 100 F 613 556 560 611 Viscosity at 210F 61.6 59. 5 60. 3 61.4 Viscosity Iudex 58. 7 59. 5 66. 0 58 Flash 0.0., F 455 455 l165 425 Neutralization No- 27 25 25 38 Vis-Gray. Constant .840 .834 .836 .841

1 Two 100% treats. 2 Two 75% treats.

From the foregoing data, it will be apparent that my improved operation allows several advantages to be obtained. These advantages may be summarized as follows:

(l) rl`he quantity of solvent required for `a given yield and viscosity index is decreased 25 percent by ruse of the water-insoluble alcohol. This also means that 25 percent more oil treating capacity can be employed than when using water as an antiesolvent. For this advantage, a comparison of Run No. 1 and Run No. 4 is in order.

3 (2),--The -treatsweremade at,30 F. below miscibili'ty temperature, Athat is 110 F. with alcohol-phenol solvent while water-phenol solvent required 170 F., thus alording an appreciable saving in heat and equipment.

Although notf.\rellected..by the ydatagnin these :operations decreased lemulsion `form-ation` fand :enhanced phase: Sepilfvx ration werefobservedfy The :alcoholf'pfh-enol solvent separated into phases ,in afew\.seconds, whereas the phenolwaterj solvent formed.; an emulsion f and; Y. separatedonlyafter standingfan, appreciable-lengthso time,` fon ex-.A

ample a ymatter: offrifteen.minutes.r The selection/ofY a miscible-f(zo-solventy with aboilinggpoint adjacent the boiling-point `ofzphenol provides.Y aniadvantage in that.' the solvent mixture` distillsasonefsolvent; andrdoes; notrequire the addition of separate solvent. Thus alcohols,- such as-'l-octanol and.2.octano1,f,boil at383 F. and 353" F. W-hicl1 I is -onfeachf sidefof fthe', boiling--4 point of Vphenol at y363 F. and;.therefor.ewould distill-vvith the-phenol;

It {Will'vbe seen -frorn1 theforegoing examples .n and the description takenfwith the;draWingfthat-anew. andimproved` operationis provided which is of considerable utility.

They naturefand objectszof the present-invention having 4 been completely; described and Killustrated/what I wish@ 2. A-frnethodA inraccordance; With-:claim 1 innwhichifthei,

alcohol is `octyl alcohol...

3. A methodinaccordance-Withs claim 2 inffwhich the amount of alcoholiis :in-.the rangeiromaaboutY 3% to about 10% by volume of saidsolvent mixture.

References Cited in the le of this patent UNITED STATES PATENTS 1,892,655"l Stratford' 1 ..Dec.' 27,` 1932 1,960,461 Stratford- .May 29; 1934" 2,280,264 Reeves Apr. 21'; 1942" 2,529,484 Carnell' Nov. 14, 1950" 2,794,839

Broughton June '4,' 1957" 

1. A METHOD FOR TREATING A LUBRICATING OIL FRACTION WHICH COMPRISES, CONTACTING SAID FRACTION WITH A SOLVENT MIXTURE OF PHENOL AND A SMALL BUT EFFECTIVE AMOUNT OF A SUBSTANTIALLY WATER-INSOLUBLE SATURATED ALIPHATIC ALCOHOL BOILING WITHIN THE RANGE FROM ABOUT 275*F. TO ABOUT 450*F. UNDER CONDITIONS TO FORM A RAFFINATE PHASE AND AN EXTRACT PHASE, SEPARATING SAID PHASE, AND SEPARATELY RECOVERING SAID SOLVENT MIXTURE FROM SAID PHASES. 